From f911ba985aa7fe0096c386c5be385ac5825ea527 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sat, 16 Jul 2005 00:30:23 +0000 Subject: Initial revision From-SVN: r102074 --- libjava/classpath/java/lang/Double.java | 521 ++++++++++++++++++++++++++++++++ 1 file changed, 521 insertions(+) create mode 100644 libjava/classpath/java/lang/Double.java (limited to 'libjava/classpath/java/lang/Double.java') diff --git a/libjava/classpath/java/lang/Double.java b/libjava/classpath/java/lang/Double.java new file mode 100644 index 00000000000..4fa47f46ddd --- /dev/null +++ b/libjava/classpath/java/lang/Double.java @@ -0,0 +1,521 @@ +/* Double.java -- object wrapper for double + Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2005 + Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.lang; + +import gnu.classpath.Configuration; + +/** + * Instances of class Double represent primitive + * double values. + * + * Additionally, this class provides various helper functions and variables + * related to doubles. + * + * @author Paul Fisher + * @author Andrew Haley (aph@cygnus.com) + * @author Eric Blake (ebb9@email.byu.edu) + * @since 1.0 + * @status updated to 1.4 + */ +public final class Double extends Number implements Comparable +{ + /** + * Compatible with JDK 1.0+. + */ + private static final long serialVersionUID = -9172774392245257468L; + + /** + * The maximum positive value a double may represent + * is 1.7976931348623157e+308. + */ + public static final double MAX_VALUE = 1.7976931348623157e+308; + + /** + * The minimum positive value a double may represent + * is 5e-324. + */ + public static final double MIN_VALUE = 5e-324; + + /** + * The value of a double representation -1.0/0.0, negative + * infinity. + */ + public static final double NEGATIVE_INFINITY = -1.0 / 0.0; + + /** + * The value of a double representing 1.0/0.0, positive infinity. + */ + public static final double POSITIVE_INFINITY = 1.0 / 0.0; + + /** + * All IEEE 754 values of NaN have the same value in Java. + */ + public static final double NaN = 0.0 / 0.0; + + /** + * The primitive type double is represented by this + * Class object. + * @since 1.1 + */ + public static final Class TYPE = VMClassLoader.getPrimitiveClass('D'); + + /** + * The immutable value of this Double. + * + * @serial the wrapped double + */ + private final double value; + + /** + * Create a Double from the primitive double + * specified. + * + * @param value the double argument + */ + public Double(double value) + { + this.value = value; + } + + /** + * Create a Double from the specified String. + * This method calls Double.parseDouble(). + * + * @param s the String to convert + * @throws NumberFormatException if s cannot be parsed as a + * double + * @throws NullPointerException if s is null + * @see #parseDouble(String) + */ + public Double(String s) + { + value = parseDouble(s); + } + + /** + * Convert the double to a String. + * Floating-point string representation is fairly complex: here is a + * rundown of the possible values. "[-]" indicates that a + * negative sign will be printed if the value (or exponent) is negative. + * "<number>" means a string of digits ('0' to '9'). + * "<digit>" means a single digit ('0' to '9').
+ * + * + * + * + * + * + * + * + * + * + *
Value of DoubleString Representation
[+-] 0 [-]0.0
Between [+-] 10-3 and 107, exclusive[-]number.number
Other numeric value[-]<digit>.<number> + * E[-]<number>
[+-] infinity [-]Infinity
NaN NaN
+ * + * Yes, negative zero is a possible value. Note that there is + * always a . and at least one digit printed after + * it: even if the number is 3, it will be printed as 3.0. + * After the ".", all digits will be printed except trailing zeros. The + * result is rounded to the shortest decimal number which will parse back + * to the same double. + * + *

To create other output formats, use {@link java.text.NumberFormat}. + * + * @XXX specify where we are not in accord with the spec. + * + * @param d the double to convert + * @return the String representing the double + */ + public static String toString(double d) + { + return VMDouble.toString(d, false); + } + + /** + * Create a new Double object using the String. + * + * @param s the String to convert + * @return the new Double + * @throws NumberFormatException if s cannot be parsed as a + * double + * @throws NullPointerException if s is null. + * @see #parseDouble(String) + */ + public static Double valueOf(String s) + { + return new Double(parseDouble(s)); + } + + /** + * Parse the specified String as a double. The + * extended BNF grammar is as follows:
+ * 

+   * DecodableString:
+   *      ( [ - | + ] NaN )
+   *    | ( [ - | + ] Infinity )
+   *    | ( [ - | + ] FloatingPoint
+   *              [ f | F | d
+   *                | D] )
+   * FloatingPoint:
+   *      ( { Digit }+ [ . { Digit } ]
+   *              [ Exponent ] )
+   *    | ( . { Digit }+ [ Exponent ] )
+   * Exponent:
+   *      ( ( e | E )
+   *              [ - | + ] { Digit }+ )
+   * Digit: '0' through '9'
+   *
+ * + *

NaN and infinity are special cases, to allow parsing of the output + * of toString. Otherwise, the result is determined by calculating + * n * 10exponent to infinite precision, then rounding + * to the nearest double. Remember that many numbers cannot be precisely + * represented in floating point. In case of overflow, infinity is used, + * and in case of underflow, signed zero is used. Unlike Integer.parseInt, + * this does not accept Unicode digits outside the ASCII range. + * + *

If an unexpected character is found in the String, a + * NumberFormatException will be thrown. Leading and trailing + * 'whitespace' is ignored via String.trim(), but spaces + * internal to the actual number are not allowed. + * + *

To parse numbers according to another format, consider using + * {@link java.text.NumberFormat}. + * + * @XXX specify where/how we are not in accord with the spec. + * + * @param str the String to convert + * @return the double value of s + * @throws NumberFormatException if s cannot be parsed as a + * double + * @throws NullPointerException if s is null + * @see #MIN_VALUE + * @see #MAX_VALUE + * @see #POSITIVE_INFINITY + * @see #NEGATIVE_INFINITY + * @since 1.2 + */ + public static double parseDouble(String str) + { + return VMDouble.parseDouble(str); + } + + /** + * Return true if the double has the same + * value as NaN, otherwise return false. + * + * @param v the double to compare + * @return whether the argument is NaN. + */ + public static boolean isNaN(double v) + { + // This works since NaN != NaN is the only reflexive inequality + // comparison which returns true. + return v != v; + } + + /** + * Return true if the double has a value + * equal to either NEGATIVE_INFINITY or + * POSITIVE_INFINITY, otherwise return false. + * + * @param v the double to compare + * @return whether the argument is (-/+) infinity. + */ + public static boolean isInfinite(double v) + { + return v == POSITIVE_INFINITY || v == NEGATIVE_INFINITY; + } + + /** + * Return true if the value of this Double + * is the same as NaN, otherwise return false. + * + * @return whether this Double is NaN + */ + public boolean isNaN() + { + return isNaN(value); + } + + /** + * Return true if the value of this Double + * is the same as NEGATIVE_INFINITY or + * POSITIVE_INFINITY, otherwise return false. + * + * @return whether this Double is (-/+) infinity + */ + public boolean isInfinite() + { + return isInfinite(value); + } + + /** + * Convert the double value of this Double + * to a String. This method calls + * Double.toString(double) to do its dirty work. + * + * @return the String representation + * @see #toString(double) + */ + public String toString() + { + return toString(value); + } + + /** + * Return the value of this Double as a byte. + * + * @return the byte value + * @since 1.1 + */ + public byte byteValue() + { + return (byte) value; + } + + /** + * Return the value of this Double as a short. + * + * @return the short value + * @since 1.1 + */ + public short shortValue() + { + return (short) value; + } + + /** + * Return the value of this Double as an int. + * + * @return the int value + */ + public int intValue() + { + return (int) value; + } + + /** + * Return the value of this Double as a long. + * + * @return the long value + */ + public long longValue() + { + return (long) value; + } + + /** + * Return the value of this Double as a float. + * + * @return the float value + */ + public float floatValue() + { + return (float) value; + } + + /** + * Return the value of this Double. + * + * @return the double value + */ + public double doubleValue() + { + return value; + } + + /** + * Return a hashcode representing this Object. Double's hash + * code is calculated by:
+ * long v = Double.doubleToLongBits(doubleValue());
+ * int hash = (int)(v^(v>>32)). + * + * @return this Object's hash code + * @see #doubleToLongBits(double) + */ + public int hashCode() + { + long v = doubleToLongBits(value); + return (int) (v ^ (v >>> 32)); + } + + /** + * Returns true if obj is an instance of + * Double and represents the same double value. Unlike comparing + * two doubles with ==, this treats two instances of + * Double.NaN as equal, but treats 0.0 and + * -0.0 as unequal. + * + *

Note that d1.equals(d2) is identical to + * doubleToLongBits(d1.doubleValue()) == + * doubleToLongBits(d2.doubleValue()). + * + * @param obj the object to compare + * @return whether the objects are semantically equal + */ + public boolean equals(Object obj) + { + if (! (obj instanceof Double)) + return false; + + double d = ((Double) obj).value; + + // Avoid call to native method. However, some implementations, like gcj, + // are better off using floatToIntBits(value) == floatToIntBits(f). + // Check common case first, then check NaN and 0. + if (value == d) + return (value != 0) || (1 / value == 1 / d); + return isNaN(value) && isNaN(d); + } + + /** + * Convert the double to the IEEE 754 floating-point "double format" bit + * layout. Bit 63 (the most significant) is the sign bit, bits 62-52 + * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 + * (masked by 0x000fffffffffffffL) are the mantissa. This function + * collapses all versions of NaN to 0x7ff8000000000000L. The result of this + * function can be used as the argument to + * Double.longBitsToDouble(long) to obtain the original + * double value. + * + * @param value the double to convert + * @return the bits of the double + * @see #longBitsToDouble(long) + */ + public static long doubleToLongBits(double value) + { + return VMDouble.doubleToLongBits(value); + } + + /** + * Convert the double to the IEEE 754 floating-point "double format" bit + * layout. Bit 63 (the most significant) is the sign bit, bits 62-52 + * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 + * (masked by 0x000fffffffffffffL) are the mantissa. This function + * leaves NaN alone, rather than collapsing to a canonical value. The + * result of this function can be used as the argument to + * Double.longBitsToDouble(long) to obtain the original + * double value. + * + * @param value the double to convert + * @return the bits of the double + * @see #longBitsToDouble(long) + */ + public static long doubleToRawLongBits(double value) + { + return VMDouble.doubleToRawLongBits(value); + } + + /** + * Convert the argument in IEEE 754 floating-point "double format" bit + * layout to the corresponding float. Bit 63 (the most significant) is the + * sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the + * exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. + * This function leaves NaN alone, so that you can recover the bit pattern + * with Double.doubleToRawLongBits(double). + * + * @param bits the bits to convert + * @return the double represented by the bits + * @see #doubleToLongBits(double) + * @see #doubleToRawLongBits(double) + */ + public static double longBitsToDouble(long bits) + { + return VMDouble.longBitsToDouble(bits); + } + + /** + * Compare two Doubles numerically by comparing their double + * values. The result is positive if the first is greater, negative if the + * second is greater, and 0 if the two are equal. However, this special + * cases NaN and signed zero as follows: NaN is considered greater than + * all other doubles, including POSITIVE_INFINITY, and positive + * zero is considered greater than negative zero. + * + * @param d the Double to compare + * @return the comparison + * @since 1.2 + */ + public int compareTo(Double d) + { + return compare(value, d.value); + } + + /** + * Behaves like compareTo(Double) unless the Object + * is not an Double. + * + * @param o the object to compare + * @return the comparison + * @throws ClassCastException if the argument is not a Double + * @see #compareTo(Double) + * @see Comparable + * @since 1.2 + */ + public int compareTo(Object o) + { + return compare(value, ((Double) o).value); + } + + /** + * Behaves like new Double(x).compareTo(new Double(y)); in + * other words this compares two doubles, special casing NaN and zero, + * without the overhead of objects. + * + * @param x the first double to compare + * @param y the second double to compare + * @return the comparison + * @since 1.4 + */ + public static int compare(double x, double y) + { + if (isNaN(x)) + return isNaN(y) ? 0 : 1; + if (isNaN(y)) + return -1; + // recall that 0.0 == -0.0, so we convert to infinites and try again + if (x == 0 && y == 0) + return (int) (1 / x - 1 / y); + if (x == y) + return 0; + + return x > y ? 1 : -1; + } +} -- cgit v1.2.3